Improving the Fabrication Process of Micro-Air-Vehicle Flapping Wings

Abstract

The aerodynamic performance of flapping micro air vehicles in hover conditions is dependent on many parameters, including the wing design. With the goal of optimizing the wing for hover performance, the initial focus was to reduce the uncertainty in the thrust measurements. This is because lower uncertainty in this metric enables better resolution in comparing the performance of different designs. Aerodynamic performance variability was deemed to be the fault of an imprecise manufacturing technique. Therefore, adjustments were made to the fabrication process until a permissible level of uncertainty was attained for optimization; the goal was less than 5%. This paper chronicles the progression of the wing fabrication process and details how the uncertainty was evaluated. Four fabrication methods and two different wing designs are included in this study: a carbon fiber hand layup technique, carbon fiber cured in a machined mold, and two variations of a machined plastic skeleton reinforced with a carbon fiber rod. The uncertainty in thrust production, expressed in coefficient of variation, improved from 16.8% for the hand layup method to 2.6% for the computer numerically controlled plastic skeleton adhered to the nylon membrane with transfer tape. Additionally, the coefficient of variation for wing weight also reduced (from 11.4 to 2.0%).